1. Field of the Invention
The present invention generally relates to seed planting implements and, more particularly, is concerned with an eccentric cam locking assembly for mounting on seed planting implements.
2. Description of the Prior Art
Many seed planting implements include a plurality of seed planting units each including means for opening a furrow in the ground, means for depositing seed in the furrow and means for closing the furrow as the seed planting implement is pulled across a field. Each means for closing the furrow typically includes a pair of furrow closing wheels, sometimes called press wheels, mounted on an arm which extends from the rear of the implement so that the closing wheels trail the implement and close the furrow after the seed is deposited in the furrow. The furrow must be properly closed to adequately cover the seed with soil and achieve the contact with the soil necessary for optimal seed germination. To properly close the seed furrow, the furrow closing wheels must be correctly aligned with the seed furrow.
Various means have been developed to properly align the furrow closing wheels with the seed furrow. In some seed planting implements, an arm on which the furrow closing wheels are mounted may be adjusted sidewise by rotation of an eccentric cam. To adjust the arm, a retaining bolt mounting the eccentric cam is loosened and the eccentric cam is turned clockwise to swing the arm and thereby move the closing wheels to the right or turned counterclockwise to swing the arm and thereby move the closing wheels to the left. When the closing wheels are properly aligned with the seed furrow, the retaining bolt is tightened to prevent further inadvertent rotation of the eccentric cam. While the eccentric cam provides a very sensitive and effective means for achieving proper alignment of the furrow closing wheels, these type of seed planting implements also have a major drawback: unintended rotation of the eccentric cam occurs causing the furrow closing wheels to move out of alignment.
As the furrow closing wheels travel through the soil, forces are applied to the wheels. These forces are transmitted from the wheels through the arm resulting in a torque on the eccentric cam. Because the wheels are mounted at the end of the arm, a small force against the wheels is magnified by the length of the arm into a large torque on the eccentric cam. The retaining bolt has proven inadequate to resist this large torque, thereby allowing unintended rotation of the eccentric cam to occur resulting in misalignment of the furrow closing wheels. Because of this unintended rotation, frequent stops are necessary to realign the furrow closing wheels while using the seed planting implement. These frequent stops reduce the efficiency of the planting process.
Consequently, a need still exists for an assembly which may be mounted on existing seed planting implements having furrow closing wheels aligned by rotation of an eccentric cam that will inhibit or prevent unintended rotation of the eccentric cam.